I'm working on parts of the Filesystem TS and think it makes sense to
split it up into separate headers for path, directory utils and the
free functions, then include those from <experimental/filesystem>,
otherwise it's going to be a whopper.
Currently I've created include/experimental/fs_path.h for the path
class, does that seem OK?
Would a new include/experimental/bits directory be better, so that
only official headers required by a TS are in include/experimental?
(That would imply moving string_view.tcc to another directory).

I'm thinking about adding an include/experimental/bits directory
again, for internal pieces of the Networking TS.
I didn't do it last time because I was too lazy, but as I'm adding
more non-public headers to include/experimental I think it makes
sense.
That patch looks like this, plus moving erase_if.h, string_view.tcc
and fs_{dir,fwd,ops,path}.h to the new bits sub-directory.
Anyone else got an opinion?